Package-on-package (PoP) is an integrated circuit packaging technology in which a number of ball grid array (BGA) packages are arranged vertically. PoP packaging beneficially reduces the board area occupied by individually semiconductor packages. PoP packaging also minimizes track length between components that frequently interoperate. Minimizing track length provides more rapid signal propagation, reduced noise, and reduced channel cross-talk. In assembly, PoP packaging permits the testing of individual components prior to stacking rather than after stacking (e.g., chip stacking), reducing rework since only known good components are used in the PoP package.
In a typical PoP integrated circuit a memory package is stacked with a logic package, such as a system-on-a-chip (SoC). Frequently, the stacked packages are stacked and then physically and conductively coupled via reforming. Since most semiconductor packages create heat when operating, heat produced by the semiconductor packages in the stack must be dissipated through a relatively small area. The reduced heat transfer within a PoP package leads to the formation of hot spots within the stack and, ultimately, to premature failure of the PoP package.
Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications and variations thereof will be apparent to those skilled in the art.